avtimer: avoid timer query from clients during SSR

Update AV timer driver to schecdule a workqueue to
make sure the ADSP on modem is up while honouring the
requests from client for timer query.

Change-Id: I3c3283e778c836fce1a68cf8a5dc439124ef2f1f
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>